Yeah I believe there is a bug here somewhere. Not sure where. We have plenty of aliases in the aliases section, but some domains which I know have aliases, are not in there. You can find their aliases by going to the aliases tab of each account, but if you search in the aliases section, they are not there.
We are on 6.0.6 network edition. The delegated admin for this domain just sees a blank list in the aliases section. global admins see other aliases, but for this particular domain, searching for them in the aliases section returns no results. HOWEVER, if you browse for them from the whole list, I can see the aliases.
I think I found the problem: "Searching for aliases returns no results in the admin console"
Displaying all aliases, or just the aliases for an account does work.
This breaks delegated admin alias managment, and makes managing lots of domains harder.
I will lodge a support request as well - please let me know if you have a bug number I can vote on.
Actually - there is an old bug about this:
Bug 19107 – Admin Console -> Aliases: search for "domain.com" doesn't show anything